It is desirable to keep the temperature of a cooling medium used to cool an electronic component as low as possible. However, if the temperature of the cooling medium is too low, dew condensation of outer air occurs in the vicinity of a pipe through which the cooling medium flows. An electronic component on which this type of dew condensation occurred could lead to a failure. Examples of the related art concerning techniques for suppressing dew condensation are Japanese Laid-open Patent Publication No. 2012-18998, Japanese Laid-open Patent Publication No. 2006-32515, Japanese Laid-open Patent Publication No. 2003-176942, Japanese Laid-open Patent Publication No. 2004-239789, and so on.
The temperature and humidity of air in the vicinity of the pipe are detected to calculate the dew point and the temperature of the cooling medium is controlled to exceed the calculated dew point, so that dew condensation does not occur on the pipe. The detection results by a temperature sensor for detecting the temperature of air and a humidity sensor for detecting the humidity include error. The dew point may be calculated on the basis of the detected temperature and detected humidity that include error. Accordingly, the calculated dew point may indicate variations. The temperature of the cooling medium is set to a value larger than the calculated dew point in consideration of such variations. It is difficult to lower the temperature of the cooling medium as low as possible in the range in which no dew condensation occurs, and the cooling capability of the cooling medium is not fully utilized in this range.